tracing: Initialize metrics with labels

Initialize tetragon_process_loader_stats with all possible event types.

Signed-off-by: Anna Kapuscinska <[email protected]>

pkg/grpc/tracing/stats.go

@@ -20,6 +20,11 @@ var (
 func InitMetrics(registry *prometheus.Registry) {
 	registry.MustRegister(LoaderStats)
 
+	// Initialize metrics with labels
+	for _, ty := range LoaderTypeStrings {
+		LoaderStats.WithLabelValues(ty).Add(0)
+	}
+
 	// NOTES:
 	// * Rename process_loader_stats metric (to e.g. process_loader_events_total) and count label (to e.g. event)?
 }